Innate constraints in vocal learning and the evolutionary process

Human language can create new meanings by arranging the order of sounds. This is a unique and a special features of language among animal vocalization. But, let’s think the language as one of the acoustic signals for communication. In this regard human language is also one of the acoustic tools like other animal sounds. While most of animals use innate vocalization for communication, a few animals can learn vocalizations after birth; for examples, language acquisition in humans and song learning in birds. I have studied how birds learn songs from their fathers after hatching and I tried to put the process in an evolutionary framework. Bird songs are affected by the reared environment as well as by the innate predisposition. The innate predisposition itself would have changed through evolution. Similarly, human language acquisition should also have been shaped by the evolutionary process. I would like to understand the mechanism of human language acquisition by linking the evolutionary approach and the language specific approach.